Virtually the first textbook I was required to buy when I entered university 20 years ago was Michael Dirr’s Manual, 4th Edition, and I’ve never been without a copy since.

A bible to horticulturists, the Sixth is more comprehensive than ever, and written in Dirr’s scholarly, yet accessible (often droll) style. For instance, when discussing Kentucky coffeetree seeds, he points out that they “are fun to throw and hit with a baseball bat,” and “in my youth I ate the sweetish gummy substance that lined the inside of the pod. Maybe that’s what is wrong with me today.” The only book about trees and shrubs you’ll ever need, with candid critiques of every woody plant grown in North America, the Sixth is the result of more than 40 years of study.